Vitamin and Mineral Nutrition of Grazing Cattle
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
E-861
Vitamin and Mineral
Nutrition of
Grazing Cattle
• Department of Animal Science •
• Oklahoma Cooperative Extension Service •
• Division of Agricultural Sciences and Natural Resources •
• Oklahoma State University •Objectives....................................................................................................................................... 1
Typical Mineral Composition of Commo Oklahoma Forages................................................ 1
Table 1................................................................................................................................................................. 2
Macro Mineral Considerations.................................................................................................... 3
Calcium....................................................................................................................................................................... 3
Phosphorus................................................................................................................................................................ 5
Figure 1............................................................................................................................................................... 6
Potassium................................................................................................................................................................... 6
Figure 2............................................................................................................................................................... 7
Magnesium................................................................................................................................................................ 7
Figure 3............................................................................................................................................................... 8
Sulfer........................................................................................................................................................................... 9
Figure 4............................................................................................................................................................. 10
Trace Mineral Considerations.................................................................................................... 10
Cobalt........................................................................................................................................................................ 10
Copper...................................................................................................................................................................... 11
Figure 5............................................................................................................................................................. 12
Iodine........................................................................................................................................................................ 12
Iron 13
Figure 6............................................................................................................................................................. 14
Manganese............................................................................................................................................................... 14
Figure 7............................................................................................................................................................. 15
Selenium................................................................................................................................................................... 15
Zinc 16
Figure 8............................................................................................................................................................. 17
Vitamins........................................................................................................................................ 16
Thiamin..................................................................................................................................................................... 17
Vitamin A.................................................................................................................................................................. 18
Figure 9............................................................................................................................................................. 19
Vitamin B12................................................................................................................................................................ 18
Vitamin D................................................................................................................................................................. 19
Vitamin E.................................................................................................................................................................. 20
Diagnosis of Mineral Deficiencies............................................................................................. 20
Table 2............................................................................................................................................................... 22
Table 3............................................................................................................................................................... 23
Table 4............................................................................................................................................................... 24
Supplementing Minerals............................................................................................................. 25
Table 5............................................................................................................................................................... 26
Conclusion.................................................................................................................................... 27
References...................................................................................................................................... 28
Notes ........................................................................................................................................... 30
Oklahoma State University, in compliance with Title VI and VII of the Civil Rights Act of 1964, Executive Order 11246 as amended, Title IX of the Education Amendments of 1972, Americans with Disabilities
Act of 1990, and other federal laws and regulations, does not discriminate on the basis of race, color, national origin, gender, age, religion, disability, or status as a veteran in any of its policies, practices, or
procedures. This includes but is not limited to admissions, employment, financial aid, and educational services.
Issued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Robert E. Whitson Director of Cooperative Extension Service,
Oklahoma State University, Stillwater, Oklahoma. This publication is printed and issued by Oklahoma State University as authorized by the Vice President, Dean, and Director of the Division of Agricultural
Sciences and Natural Resources and has been prepared and distributed at a cost of 99 cents per copy. 0209 GH Revised.E-861•1
by David Lalman and Casey McMurphy 2. Summer native range and prairie hay require
phosphorus supplementation.
3. Most grasses common to Oklahoma are marginal to
Objectives deficient in copper and zinc.
• Discuss mineral composition of Oklahoma 4. It is apparent that good quality legume-based forages
forages require very little if any mineral supplementation
• Consider mineral needs of cattle with the exception of zinc and salt, depending on the
• Discuss the effects of mineral deficiencies amount of this type of hay provided in the total diet.
• Recommend mineral supplementation programs 5. In addition, fescue forage is usually marginal to
deficient in selenium, while Bermudagrass forage is
Proper mineral and vitamin nutrition contributes marginal.
to strong immune systems, reproductive performance,
and calf weight gain. A properly balanced mineral Remember that these values represent averages
program requires consideration of previous cow and and that variation from location to location can be quite
calf mineral nutrition, hay or pasture forage intake and extreme.
mineral concentration, and feed or mineral supplement
intake and mineral concentration. Diets with mineral As discussed in the next section, each of these
imbalances may cause poor animal performance, marginal to deficient minerals has been shown to impact
resulting in reduced profitability. immune function, reproduction, or both. Therefore, it is
recommended that producers make certain that beef
Mineral requirements are dependent on forage cows receive supplemental sources of these elements at
mineral content, animal age, and stage of production. least 60 days prior to calving through breeding and 30
However, simply knowing the animal’s requirement is to 60 days prior to weaning. Similarly, weaned calves
only one component in evaluating an animal’s mineral and purchased stocker cattle should receive adequate
status. Mineral needs also tend to be area specific and copper, zinc, and selenium through a concentrate feed
change with soil type, fertilization rates, rainfall, and supplement or free-choice mineral.
other factors. An understanding of the need for minerals
is necessary for making decisions about what and how
much mineral to feed. Major attention here will be
Macro Mineral Considerations
focused on those minerals most likely to pose a problem
in Oklahoma. Calcium
Calcium is an important mineral for beef cattle, both
in terms of the relative requirement and the diversity of
Typical Mineral Composition functions in the body. It is a major component of the
of Common Oklahoma Forages skeleton, which also serves as a calcium storage site. In
As a general rule, Oklahoma forages do not have fact, about 99% of the total calcium in the body is found
severe mineral deficiencies or high levels of mineral in the bones and teeth.
antagonists compared to forages in many other states.
When excessive amounts of antagonistic minerals are Calcium is involved in blood clotting, muscle
consumed, the availability of other minerals is reduced contraction, transmission of nerve impulses, regulation of
or completely blocked. Specific antagonists are discussed the heart, secretion of hormones, and enzyme activation
more extensively in the next section. However, forage and stabilization. Fortunately, calcium is available in
mineral concentration is extremely variable and site- adequate amounts in high quality forages, although
specific mineral problems in Oklahoma have been calcium can be deficient in weathered or mature forage.
identified. The most frequently observed cases of calcium deficiency
occur in cattle fed high amounts of concentrate feed
Table 1 shows average mineral concentration in four and in cattle grazing small grain forages. Availability
types of forages common to Oklahoma and compares of dietary calcium is also quite variable. Consequently,
these averages with requirements of growing cattle. the National Research Council assumed dietary calcium
The data shown in Table 1 was summarized from two availability was only 50% when calcium requirements
large data sets over a period of several years. These data were calculated. Signs of calcium deficiency include:
represent forage mineral concentration when samples • Rickets: weak, soft bones in young cattle; retards
were harvested during mid-summer. Remember that bone growth and performance of young growing
forage will contain much higher concentration of most cattle
minerals when it is immature and rapidly growing • Osteomalacia: weak brittle bones caused by
compared to more mature, weathered forage. demineralization of bones in adult animals
• Urinary calculi: hard masses of mineral salts and
From these data, several general principles are tissue cells that form in the kidney or bladder and
evident relative to supplementing minerals to grazing can cause water belly in growing steers and bulls
beef cattle in Oklahoma.
1. Almost all forage requires salt supplementation as a Problems may arise due to low calcium content of
source of sodium. grains, small grain forage, and many byproduct feeds.E-861•2
Table 1. Average mineral concentration of common Oklahoma forages and dietary requirements of beef cattle.
Forage Type Dietary Requirement of
Mineral Alfalfa/Clover Bermudagrass Fescue Native Beef Cattlea
Phosphorus, % 0.27 0.21 0.23 0.08 0.15 to 0.3
Sodium, % 0.08 0.04 0.02 0.01 0.06 to 0.08
Iron, ppm 198 114 110 190 50.0
Copper, ppm 12.4 6.3 5.0 5.7 10.0
Zinc, ppm 23 22.4 17.8 22.5 30.0
Selenium, ppm 0.3 0.15 0.09 0.21 0.10
Manganese, ppm 47.6 83.9 122 51.6 20.0
a Adapted from NRC, 2000.
While forages tend to be adequate in calcium and deficient the essential trace minerals. Therefore, producers should
in phosphorus, the opposite is true of small grain forage strive to maintain dietary Ca:P ratios of less than 3:1 and
and grains such as corn, milo, barley, oats, and wheat. above 1.5:1.
These grains will typically contain about 0.03% calcium
and about 0.3% phosphorus. Similarly, corn gluten feed, The other calcium deficiency occasionally observed
wheat middlings, barley malt sprout pellet products, in Oklahoma occurs when pregnant and lactating cows
and many other concentrate feeds contain 0.5% to over graze lush cool-season forage, such as small grains,
1% phosphorus. The phosphorus content is adequate brome, and fescue. These cool-season forages are high
for most cattle but the calcium content is extremely low in phosphorus and low in calcium during immature
compared to the animal’s requirement. In this situation, stages of growth. When cows in late pregnancy and
the problem of low dietary calcium is compounded by early lactation graze this type of forage, grass tetany is
the low ratio of calcium to phosphorus. frequently observed. Originally, the problem was thought
to be solely the result of magnesium deficiency. However,
When dietary phosphorus exceeds dietary calcium, more recent studies have shown that tetany may result
absorption of calcium from the digestive tract is further from calcium deficiency as well as from magnesium
reduced. Therefore, when significant amounts of these deficiency. Symptoms of tetany from deficiencies of
concentrates are fed without supplemental calcium, the both minerals are indistinguishable without blood tests
animal will metabolize bone calcium to meet the body’s and the treatment consists of intravenous injections of
requirement. However, the calcium in the bone is stored calcium and magnesium gluconate, which supplies
in combination with phosphorus and both must be both minerals. Cows grazing lush small grains pastures
mobilized at the same time. Therefore, both calcium and should be fed mineral mixes containing both calcium
phosphorus in the bone will be depleted. and magnesium.
Another nutritional disease that can develop in Phosphorus
growing male cattle with adequate or high phosphorus Phosphorus is often discussed in conjunction with
and low calcium is water belly or urinary calculi. calcium because these minerals interact in many bodily
The most effective method to prevent urinary calculi functions and because they are both stored in bone tissue.
development in growing male cattle is to maintain total Phosphorus, along with calcium, is a major component
dietary calcium to phosphorus ratio of between 1.5:1 and in bone structure with over 80% of the phosphorus in the
3:1. Most nutritionists formulate rations and mineral body residing in bone and teeth. However, phosphorus
supplements to achieve a ratio of around 2:1. Calcium is has many other important physiological roles including
an inexpensive mineral to add and a general rule of 1% cell growth and differentiation; energy utilization
added limestone will balance the calcium requirement and transfer; cell membrane structure, primarily as
in most grain-based rations. phospholipids; and acid-base and osmotic balances.
Phosphorus is also required by ruminal microorganisms
A second method to minimize the risk of this for growth and cellular metabolism. Signs of phosphorus
disease is to make certain the cattle have access to salt or deficiency include:
the total diet contains 0.5% up to 4% salt. Salt increases • Osteomalacia: weak, brittle bones caused by
water intake, which increases mineral solubility and demineralization of bones in adult animals
dilutes the urine. • Infertility
• Reduced feed intake, growth and feed efficiency
Cattle can tolerate calcium to phosphorus ratios of • Reduced milk production
up to about 7:1. However, excessive calcium has been • Pica (chewing and gnawing wood and other
shown to reduce absorption of phosphorus and many of objects)E-861•3
0.3
0.8
0.2
P, % DM
0.6
0.1
K, % DM
0.4
0
Nov Dec Jan Feb Mar 0.2
Figure 1. Effects of weathering on phosphorus
concentration of stockpiled bermudagrass forage. 0
Source: Lalman, et al., 2002.
Nov Dec Jan Feb Mar
Phosphorus may be deficient in Oklahoma forages Figure 2. Effects of weathering on potassium
during several months of the year, with great apparent concentration of stockpiled bermudagrass forage.
variation from area to area. Forage phosphorus Source: Lalman et al., 2002.
concentration and digestibility declines with advanced standing forage or hay that is rained on after cutting
maturity and weathering. Figure 1 shows the decline of and before baling. Figure 2 shows a 76% decline in
phosphorus concentration in stockpiled Bermudagrass K concentration in standing forage from November
forage through the winter months. In this and subsequent to March. Nebraska research showed that winter
figures, the box represents the range in phosphorus supplements should contain about 2% potassium when
requirements for most classes of beef cattle, according to fed at rates of 1.5 to 2.0 lb/hd/day, or about 10 grams of
NRC. It is apparent that this forage resource contained supplemental potassium/hd/day.
adequate phosphorus during the early fall months,
although phosphorus would need to be supplemented Common sources of supplemental potassium
for all classes of cattle during late winter because forage include potassium chloride (KCL) and potassium
phosphorous declined by 39%. carbonate (K2CO3). The carbonate form is more palatable
than the chloride form.
The wide range in phosphorus content of forages
in the state highlights the need for forage testing. A Because soybean meal and cottonseed meal both
forage test that includes calcium and phosphorus contain more than 1.5% K and sunflower meal and
will cost around $30. Considering the potential cost peanut meal contain more than 1.2% K, the requirement
of over feeding phosphorus when it is not needed or for potassium is met when natural protein supplements
the potential lost performance when phosphorus is are fed. Alfalfa hay, cubes, and dehydrated pellets are
underfed, the advantages of sampling are obvious. It also excellent sources of potassium, containing between
should be remembered that phosphorus deficient cattle 1.5 to 3%. If grain-based urea supplements are fed that
may show varying degrees of unthriftiness long before do not contain substantial amounts of the oilseed meals,
classical signs such as bone and joint deformities appear. potassium will need to be added. KCL is the most
The rumen will likely be phosphorus deficient before the common source used in livestock rations.
animal’s body has mobilized bone reserves. Phosphorus
deficient animals will appear malnourished.
Magnesium
Magnesium is closely related to calcium and
Potassium phosphorus in function and distribution in the body.
Potassium (K) is the third most abundant mineral in This mineral is known to activate at least 300 different
the body. It is important in acid-base balance, regulation enzymes. Magnesium is essential in energy metabolism,
of osmotic pressure and water balance, muscle transmission of the genetic code, membrane transport,
contractions, nerve impulses, and certain enzyme and nerve impulse transmissions. Magnesium is available
reactions. Signs of potassium deficiency include: in several common forms with the most common being
• Reduced feed intake and weight gain magnesium oxide and magnesium sulfate (epsom salts).
• Pica (chewing and gnawing wood and other Signs of magnesium deficiency include:
objects) • Excitability
• Rough haircoat • Anorexia
• Muscular weakness • Hyperemia
• Convulsions and muscular twitching
When forage is growing and immature, potassium • Frothing at the mouth
concentration is high and generally exceeds the • Profuse salivation
requirements of all classes of cattle. However, potassium • Calcification of soft tissue
is soluble in plant tissue and is rapidly depleted in • Grass tetanyE-861•4
When conditions for occurrences of tetany
0.25 are suspected, cows should be provided a mineral
NRC supplement containing between 6 and 30% magnesium
0.2 with daily mineral intake ranging from 2 to 4 oz per
Mg, % DM
0.15 day. The higher inclusion rate and level of intake
is appropriate for high-risk situations. In high-risk
0.1 situations, cows should consume around 1 oz of
0.05 magnesium oxide per day. This is difficult because
magnesium oxide is very unpalatable to cattle. Most
0 commercial products formulated for the purpose of
Nov Dec Jan Feb Mar minimizing the risk of grass tetany contain between 6
and 15% magnesium. It is best for the high-magnesium
Figure 3. Effects of weathering on magnesium supplements to be provided at least one month ahead
concentration of stockpiled bermudagrass forage. of the period of tetany danger so that proper intake can
Source: Lalman et al., 2002. be established. Because tetany can occur when calcium
is low as discussed in the phosphorus section, calcium
supplementation should also be included. Examples of
high-magnesium mineral supplements are shown in
Figure 3 indicates that the reduction in standing Table 4 on page 11.
forage magnesium concentration can be substantial
during the winter months. In fact, in this experiment, A key point should be made here. Magnesium
Bermudagrass forage magnesium concentration supplementation does not cure or prevent bloat in
declined about 50% from November through March. cattle grazing wheat pasture. Tetany and bloat are two
different problems with tetany affecting older cows and
Grass tetany typically occurs in beef cows during bloat being a major problem with younger stocker cattle.
early lactation and is more prevalent in older cows. Older While calcium and magnesium may be very effective in
cows are thought to be less able to mobilize magnesium preventing tetany, they are ineffective for preventing
reserves from bone compared to younger cows. Grass bloat.
tetany most frequently occurs when cattle are grazing
lush immature grasses or small grains pastures and
tends to be more prevalent during periods of cloudy Sulfur
weather. Symptoms include uncoordination, salivation, Sulfur is needed for synthesis of methionine and
excitability (cows may charge humans), and, in the final cystine, which are sulfur-containing amino acids, as well
stages, tetany, convulsions, and death. Grass tetany is as the B vitamins, thiamin, and biotin. Sulfur is required
occasionally encountered on fescue pastures but the by ruminal microorganisms for normal growth and
incidence is much lower than seen on small grains. metabolism. In fact, ruminal microorganisms are capable
of synthesizing all organic sulfur containing compounds
It is known that factors other than simply the required by the animal from inorganic sulfur.
magnesium content of the forage can increase the
probability of grass tetany. Some of these factors are Although sulfur deficiency is very uncommon in
discussed in the phosphorus section above. High Oklahoma, signs of sulfur deficiency include:
levels of potassium in forages can decrease absorption • Anorexia, weakness, dullness, emaciation
of magnesium, and many lush, immature forages are • Excessive salivation
high in potassium. Consequently, the incidence of • Death
grass tetany on wheat pasture often occurs in central
and western Oklahoma on soils that are quite high in Sulfur concentration was above that suggested
potassium. High levels of nitrogen fertilization have by NRC as the dietary requirement and declined only
also been shown to increase the incidence of tetany, slightly (16%) in standing Bermudagrass forage through
possibly because an insoluble precipitate of magnesium- the winter (Figure 4).
ammonium-phosphate forms in the digestive tract and is
excreted by the animal. Feeding supplements containing Marginal deficiencies would be expected to result
high concentrations of nonprotein nitrogen to cattle in reduced feed or forage intake and digestibility due to
grazing lush forage would also increase the risk of grass reduced ruminal microorganism growth and metabolism.
tetany. Feeding oilseed meal-based protein supplements Sulfur supplementation might be considered when
has not been shown to increase the incidence of tetany, urea-based protein supplements containing little natural
although this could contribute to the bloating problem protein are fed. Otherwise, there is little likelihood that
especially with stocker cattle. supplemental sulfur will be needed.
Other factors such as the presence of certain organic Cattle are very sensitive to excessive sulfur intake
acids in tetany-prone forages have been linked with through water and feed. The maximum tolerable
tetany. It is likely that a combination of factors, all related concentration of dietary sulfur has been estimated
to characteristics of lush forage, are involved. to be 0.4%. Sulphate sulfur in drinking water should
not exceed 500 mg/L. Diets high in sulfur can causeE-861•5
0.3 in cattle is assessed using blood serum concentrations of
vitamin B12. Cattle with 200 nanograms/mL or higher
serum B12 concentration are thought to have adequate
ruminal B12 synthesis. Signs of cobalt deficiency include:
S, ppm
0.2 • Reduced appetite
• Reduced growth rate or failure to moderate weight
loss in cows
NRC
• Pale skin and mucous membranes
0.1
• Reduced ability of neutrophils to kill yeast
• Reduced disease resistance
0 Young rapidly growing cattle seem more susceptible
to cobalt deficiency than mature cattle. Feed-grade
Nov Dec Jan Feb Mar
sources of cobalt include sulfate, carbonate, and chloride
forms as well as commercial products containing organic
Figure 4. Effects of weathering sulfur concentration of
forms of cobalt.
stockpiled bermudagrass forage. Source: Lalman et al.,
2002.
Copper
Copper is an important cofactor in many enzyme
polioencephalomalicia (PEM). Signs of PEM include systems including those involved in hemoglobin
restlessness, diarrhea, muscular twitching, dyspnea formation, iron absorption and mobilization, connective
(labored breathing), blindness, and in prolonged tissue metabolism, and immune function. Copper status
cases, inactivity followed by death. It is important for in cattle is quite susceptible to a number of antagonists,
cattle producers to recognize that some common feed including molybdenum, sulfur, iron, and zinc. When total
commodities, such as soybean meal, distillers grains, intake (dietary and water) of these potential antagonists
corn gluten feed, and barley malt sprout pellets, may is within the normal or adequate range, copper status is
contain between 0.4 and 1% sulfur. Therefore, if feeds likely not affected. However, when daily intake of one or
high in sulfur make up a high percentage of the animal’s more of these antagonists is higher than what is needed
daily dry matter intake, PEM is a real threat. Generally, to meet the animal’s requirements, reduced copper status
if forage, water, and other feed sources are low in sulfur can occur. In these cases, copper supplementation must
concentration, feeding up to 1% of body weight of high be increased accordingly to gradually restore the animal
sulfur containing supplements will not cause a problem. to normal copper status. Signs of copper deficiency
Obviously, if there is a concern or a question about the include:
sulfur concentration of any feed source, a representative • Anemia
sample should be submitted to a commercial feed testing • Reduced growth rate
laboratory for sulfur analysis. • Depigmentation (dulling) of hair and rough hair
coat
Diets that contain greater than 0.35% sulfur and • Diarrhea
water containing high sulfur concentration have been • Reduced fertility
implicated in initiating copper deficiency in cattle. High • Increased incidence of abomasul ulcers in newborn
levels of forage sulfur are likely when ammonium sulfate calves
or other fertilizer sources high in sulfur are used. • Reduced immune function; increased bacterial
infections
Trace Mineral Considerations
Trace minerals are those that are required only Copper concentration of stockpiled Bermudagrass
in extremely small amounts. Because such small forage was well below the NRC suggested requirement,
daily quantities of trace minerals are needed, dietary and concentration declined by 20% between November
requirements are generally expressed in parts per million and March (Figure 5).
(ppm), rather than percent. Trace mineral requirements
are not well defined and deficiencies are frequently Copper status is best assessed by collecting liver
difficult to pinpoint due to the inconspicuousness and tissue via biopsy and analyzing the wet tissue for mineral
overlap of deficiency symptoms among minerals. concentration. Copper oxide is extremely low in terms
of its availability to the animal, whereas the sulfate and
various organic forms are much higher in availability.
Cobalt Copper oxide should not be used to supplement cattle
Cobalt’s primary role in ruminants is a building
when a copper deficiency has been determined to exist.
block for vitamin B12. This essential vitamin can be
Molybdenum and sulfur in the rumen combine to form
manufactured in the rumen by the microorganisms when
thiomolybdates, which form a complex with copper that
cobalt and other precursors are available. Vitamin B12
is essentially unavailable to the animal. Most nutritionists
catalyzes enzymes that are essential in energy metabolism
agree that the dietary copper to molybdenum ratio
and methionine (an amino acid) metabolism. Very little
should be maintained between 4:1 and 10:1 in order
cobalt is stored in body tissues. Therefore, cobalt statusE-861•6
Clinical signs of iodine deficiency may not be
12 apparent for up to one year after the iodine deficient diet
NRC is initiated. Iodine supplementation is inexpensive and
10 easily provided through iodized salt. Iodine is usually
provided in supplements in the form of calcium iodate
8 or ethylinediamine dihydroiodide (EDDI), an organic
form of iodine. High temperatures, high humidity,
Cu, ppm
6 and rain volatilize and leach iodine in salt and mineral
mixtures.
4
2 Iron
Iron is an essential component in the structure of
0 proteins involved in transportation and utilization of
Nov Dec Jan Feb Mar oxygen. Examples include hemoglobin, myoglobin,
cytochromes, and iron-sulfur proteins involved in the
Figure 5. Effects of weathering on copper concentration electron transport chain. Additionally, as with many
of stockpiled bermudagrass forage. Source: Lalman et other trace minerals, several enzymes either contain
al., 2002. or are activated by iron. Signs of iron deficiency may
include:
• Anemia
to minimize the risk of molybdenum induced copper • Anorexia
deficiency. Therefore, when forage copper concentration • Reduced growth rate or increased rate of weight
is adequate (around 10 ppm) and forage molybdenum loss
concentration is high, a supplemental source of copper • Listlessness
will still be needed. • Pale mucous membranes
• Atrophy of the papillae of the tongue
Copper and zinc are absorbed through similar
pathways creating a competition for absorption sites. Iron deficiency in grazing cattle is unlikely because
Therefore, mineral supplements should be formulated most forages contain more iron than is necessary to meet
with a copper to zinc ratio of around 1:2 or 1:3. this requirement (Figure 6). Additionally, most feed
grains and oilseed meals contain significant amounts of
Forage-based diets containing 250 to 1,200 ppm iron. Cattle can also ingest iron through the water source
iron in the form of iron carbonate reduces copper and soil ingestion. In fact, many soils in Oklahoma
status in cattle. For some reason iron-induced copper contain high concentrations of iron oxide, which gives
deficiency has yet to result in typical clinical signs it the red or reddish-brown appearance. This high soil
associated with copper deficiency, particularly growth concentration leads to high forage iron concentration.
rate and reproduction effects. However, iron-induced Heavy parasite infestations or other diseases causing
copper deficiency has resulted in pancreatic damage chronic blood loss can lead to an iron deficiency.
and impaired neutrophil function, suggesting reduced
function of the immune system. Supplemental iron sources include ferrous (iron)
sulfate, ferrous carbonate, and ferric (iron) oxide.
Availability of ferrous sulfate is high, while ferric oxide
Iodine is very low in availability. Many commercial mineral
Iodine is an essential component of the thyroid mixes include ferric oxide to give it the traditional red
hormones thyroxine (T4) and triiodothyronine (T3), appearance.
which regulate the rate of energy metabolism in the body.
Iodine requirements may be elevated in cattle consuming
goitrogenic or goiter causing substances, which interfere
with iodine metabolism. The cyanogenetic goitrogens
600
include the thiocyanate derived from cyanide in white
clover and the glucosinolates found in some forages 500
such as kale, turnips, and rape. These goitrogens impair 400
Fe, ppm
iodine uptake by the thyroid, and their effect can be 300
overcome by increasing dietary iodine. Signs of iodine
200
deficiency include:
100 NRC
• Swelling of the thyroid gland, particularly in the
newborn 0
• Hairless, weak calves at birth Nov Dec Jan Feb Mar
• Low reproductive rate in cows
Figure 6. Effects of weathering on iron concentration
• Retained placenta
of stockpiled bermudagrass forage. Source: Lalman et
• Decreased libido and semen quality in males
al., 2002.E-861•7
Dietary iron concentrations as low as 250 to 500 manganese sulfate. High intake of phosphorous, calcium,
ppm have caused copper deficiency in cattle. Many and iron results in reduced manganese absorption.
water sources and forages in Oklahoma are high
in iron concentration. In these situations, copper Selenium
supplementation may need to be provided to prevent Early attention was drawn to selenium because of
copper deficiency. High iron intake has also been severe selenium toxicity in grazing cattle in some parts
implicated in reducing manganese absorption in cattle. of the U.S. More recently, forage selenium concentration
has been shown to be marginal to deficient in several
Manganese areas. Unlike many other trace minerals, the range
Manganese is important in bone growth and between dietary toxicity and deficiency is quite narrow.
formation in young animals and in maintaining In fact, the USDA regulates the inclusion rate of selenium
optimum fertility in female cattle. The role of manganese in feeds and supplements with levels not to exceed 3 mg
in metabolism includes a component of the enzymes per day or about 0.14 mg /lb of total diet (0.3 ppm). This
pyruvate carboxylase, arginase, superoxide dismutase, amount is equivalent to only 0.7 gm of total selenium
and several others. Signs of manganese deficiency per ton of feed.
include:
• Skeletal abnormalities in young cattle resulting in Selenium is required in the body for synthesis
stiffness, twisted legs, enlarged joints, and reduced of an enzyme that breaks down harmful oxidizing
bone strength agents. Selenium and vitamin E are somewhat related
• Low reproductive performance in mature cattle because vitamin E acts to protect cells from the harmful
• Abortions effects of the oxidizing agents. Vitamin E also acts as an
• Stillbirths antioxidant. Therefore, a deficiency of either selenium
• Low birth weights or vitamin E will increase the requirement for the other.
Early work suggested that selenium supplementation
The necessity for manganese supplementation may moderate the negative effects of fescue toxicosis.
in grazing cattle remains unclear. Forage and feed Unfortunately, initial positive claims for beneficial
manganese concentrations are generally well above the effects of selenium against fescue toxicity have not been
concentration suggested for the dietary requirement of substantiated in studies at the University of Missouri.
cattle (20 to 40 ppm) as shown in Figure 7. In this study, However, on average, fescue forage is marginal to low
Bermudagrass forage manganese concentration was in selenium concentration, suggesting that a low level
more than twice the dietary requirement throughout the of supplementation may improve animal performance.
winter. Signs of selenium deficiency include:
• White muscle disease: degeneration and necrosis of
However, limited research suggests that the skeletal and cardiac muscle
availability of forage manganese is quite low (less than • Reproductive failure
20%). Until more research is available, and considering • Increased incidence of retained placenta in dairy
the importance of manganese in cow fertility and cows
in young calf development, it seems logical to focus • Increased calf mortality and reduced calf weaning
supplementation and diet evaluation efforts prior to and weights
immediately following calving. • Immune suppression
Effective manganese sources include manganese Sodium selenite is the most common form of
sulfate, manganese oxide, and various organic forms of selenium supplementation, although several organic
manganese. Relative availability of organic sources of forms of selenium have recently been developed.
manganese is approximately 120% of manganese sulfate
with manganese oxide having lower availability than Producers should be cautioned against attempting
to mix their own formulation with selenium. The toxic
level for selenium is only 10 times the requirement and
150 any math error or mixing mistake can lead to serious
125 consequences.
100
Mn, ppm
75
Zinc
Zinc is an essential component of a number of
50 NRC important metabolic enzymes and it serves to activate
25 numerous other enzymes. Enzymes that require zinc
0 are involved in protein, nucleic acid, and carbohydrate
Nov Dec Jan Feb Mar metabolism as well as enzymes associated with immune
function. Signs of zinc deficiency include:
Figure 7. Effects of weathering on manganese • Reduced feed intake and growth rate
concentration of stockpiled bermudagrass forage. • Listlessness
Source: Lalman et al., 2002. • Excessive salivationE-861•8
40 significant concern for grazing cattle in Oklahoma will
NRC be discussed.
30
Thiamin
Zn, ppm
20
Thiamin functions in all cells as a coenzyme
cocarboxylase. Thiamin is the coenzyme responsible
10
for all enzymatic carboxylations of keto-acids in the
tricarboxylic acid cycle, which provides energy to
0
Nov Dec Jan Feb Mar the body. Thiamin also plays a key role in glucose
metabolism.
Figure 8. Effects of weathering on zinc concentration
of stockpiled bermudagrass forage. Source: Lalman et Synthesis of thiamin by rumen microflora makes it
al., 2002. difficult to establish a ruminant requirement. Generally,
animals with a functional rumen can synthesize adequate
amounts of thiamin.
• Reduced testicular growth
• Swollen, cracked hooves In all species, a thiamin deficiency results in
• Skin lesions (parakeratosis) central nervous system disorders, because thiamin is an
• Failed or slowed wound healing important component of the biochemical reactions that
• Reduced fertility in cows and bulls break down the glucose supplying energy to the brain.
Other signs of thiamin deficiency include weakness,
Most forages are marginal to low in zinc retracted head (head back and cannot look down),
concentration compared to the suggested requirement and cardiac arrhythmia. As with other water-soluble
(30 ppm). Figure 8 shows the zinc concentration in vitamins, deficiencies can result in slowed growth,
stockpiled Bermudagrass forage throughout the winter. anorexia, and diarrhea.
Although zinc concentration was below the requirement,
forage zinc concentration did not decline as the winter
grazing season progressed. Vitamin B12
B-vitamins are abundant in milk and other feeds.
Previously it was noted that mineral supplements B-vitamins are synthesized by rumen micro-organisms,
should contain a copper to zinc ratio between 1:2 and beginning soon after a young animal begins feeding.
1:3. Zinc sulfate, zinc oxide, and organic forms of zinc As a result, B-vitamin deficiency is limited to situations
are common supplementation sources. Absorption or where an antagonist is present or the rumen lacks the
availability is lower for the oxide compared to the sulfate precursors to make the vitamin.
and organic forms.
Vitamin B12 is the generic descriptor for a group of
compounds having vitamin B12 activity. One feature of
Vitamins vitamin B12 is that it contains 4.5% cobalt. The naturally
Vitamins and vitamin precursors are organic occurring forms of vitamin B12 are adenosylcobalamin
components of forage and feeds, although they are and methyl cobalamin. These are found in both plant
distinct from carbohydrates, protein, fat, and water. and animal tissues. The primary functions of vitamin
Vitamins are essential for the development and B12 involve metabolism of nucleic acids, proteins, fats,
maintenance of different tissues and they are involved and carbohydrates. Vitamin B12 is of special interest in
in numerous metabolic activities. Vitamins also differ ruminant nutrition because of its role in propionate
from other essential nutrients in that they do not enter metabolism, as well as the practical incidence of vitamin
into the structural portions of the body. B12 deficiency as a secondary result of cobalt deficiency.
Primarily, cobalt content of the diet is the limiting factor
Vitamins are classified as either fat-soluble (A, for ruminal microorganism synthesis of vitamin B12.
D, E, and K) or water-soluble (B, thiamin, niacin, and
choline) based upon their structure and function. Fat- 250
Micrograms/gram
soluble vitamins contain only carbon, hydrogen, and
200
oxygen, whereas the water-soluble B-vitamins contain
these elements and either nitrogen, sulfur, or cobalt. 150
Fat-soluble vitamins may occur in plant tissues as a
100
provitamin (a precursor to the vitamin). A good example
is carotene in forages, which is readily converted to 50
vitamin A by ruminant animals. No provitamins are 0
known to exist for the water-soluble vitamins. However,
rumen microorganisms have the ability to synthesize A M J J A S O N D J F M
water-soluble vitamins. As a result, the supplementation
Figure 9. Concentration of carotene in native range
of water-soluble vitamins is generally not necessary
forage. Source: Wuller et al., 1972.
in ruminants. Only the vitamins thought to be ofE-861•9
A vitamin B12 deficiency is difficult to distinguish and derived from the precursor 7-dehydrocholesterol.
from a cobalt deficiency. The signs of deficiency may One IU of vitamin D is equivalent to 0.025 microgram of
not be specific and can include poor appetite, retarded vitamin D3 or vitamin D2. Similarly, 1 mg of either source
growth, and poor condition. In severe deficiencies, contains 40,000 IU activity.
muscular weakness and demyelination of peripheral
nerves occurs. In young ruminant animals, vitamin B12 Sun-cured hay, irradiated yeast, and certain fish
deficiency can occur when rumen microbial flora have liver oils contain high concentrations of vitamin D.
not reached adequate populations or are depleted due However, because vitamin D is synthesized by beef
to stress. cattle when exposed either to sunlight or fed sun-cured
forages, they rarely require vitamin D supplementation.
Vitamin A Examples of situations conducive to moderate vitamin
Vitamin A is considered by many to be the D deficiency would include cattle housed indoors for
most important vitamin regarding the need for long periods of time and fed a high-concentrate ration
supplementation. Vitamin A is necessary for proper (little or no sun-cured forage), and cattle consuming
bone formation, growth, vision, skin and hoof tissue extremely low quality forage during long periods with
maintenance, and energy metabolism (glucose synthesis). little or no sunlight.
Deficiency symptoms include:
• Night blindness Severe vitamin D deficiency results in a disease
• Reproductive failure referred to as rickets, which is caused by the bones failure
• Skeletal deformation to assimilate and use calcium and phosphorus normally.
• Skin lesions Accompanying evidence frequently includes a decrease
in calcium and inorganic phosphorus in the blood,
Plant materials contain the provitamin, carotene. swollen and stiff joints, anorexia, irritability, tetany,
Green leafy forage, green hay, silages, dehydrated alfalfa and convulsions. Osteomalacia is a related disease that
meal, yellow corn, whole milk, and fish oils are rich affects older animals with vitamin D deficiency, resulting
sources of carotene. In cattle, 1 mg of beta-carotene is in weak, fragile bones.
converted to the equivalent of about 400 international
units (IU) of vitamin A. Lush immature forage contains Vitamin E
high concentrations of carotene, although carotene is Vitamin E occurs naturally in feedstuffs as
destroyed rapidly as the plant matures and with exposure α‑tocopherol. Vitamin E is not stored in the body in large
to sunlight, air, and high temperatures (Figure 9). concentrations, although small quantities can be found in
the liver and adipose tissue. This vitamin serves several
The liver does store vitamin A, and these stores functions including a role as an inter- and intra-cellular
can serve to prevent deficiency in times when carotene antioxidant and in the formation of structural components
or vitamin A intake is low. It is generally thought that of biological membranes. Vitamin E is important in muscle
vitamin A stores can last only 2 to 4 months if a severe growth and structure.
dietary deficiency exists. Situations where cattle are
particularly susceptible to vitamin A deficiency includes The vitamin E requirement for cattle has not been
times when cattle consume: firmly established. For young growing cattle, the
• High-concentrate diets requirement is estimated to be between 7 and 27 IU/lb
• Winter pasture, crop residues, or hay growing of feed dry matter. However, 50 to 100 IU/hd/day has
during drought conditions been suggested for older growing and finishing cattle
• Feeds receiving excess exposure to sunlight, air, and (NRC).
high temperature
• Feeds that have been heavily processed or mixed Vitamin E deficiencies can be initiated by the intake
with oxidizing materials, such as minerals of unsaturated fats. Examples of common sources of
• Forages that have been stored for long periods of unsaturated fats include whole cottonseed, soybeans,
time and whole sunflowers, among others.
Vitamin D Signs of deficiencies in young calves are characteristic
Vitamin D is essential for bone growth and of white-muscle disease including general muscular
maintenance because it is directly involved in calcium dystrophy, weak leg muscles, crossover walking, impaired
absorption as well as phosphorus absorption from suckling ability caused by dystrophy of tongue muscles,
the kidney and it is involved in osteoblast (bone cell) heart failure, paralysis, and hepatic necrosis.
formation and calcification. It also plays an important role
in phosphorylation of carbohydrates, which is part of the
energy metabolism process, and it has a regulatory role
Diagnosis of Mineral Deficiencies
Diagnosis of mineral deficiencies is difficult due
in immune cell function. There are two primary forms of to extreme variation in current and historical dietary
vitamin D: 1. ergocalciferol (vitamin D2) derived from the mineral supply, the presence of potential antagonists,
plant steroid, ergosterol, and 2. cholecalciferol (vitamin differences in the availability of minerals in various
D3), which is found only in animal tissues or productsE-861•10
supplement sources, and only a cloudy view of specific potential cause of severe or even marginal deficiency
dietary mineral requirements, particularly for trace signs, such as low pregnancy rates or high morbidity
minerals. An effective diagnosis may include several of and mortality rates in weaned calves, tissue and water
the following evaluations: clinical signs, soil analysis, source evaluations may be necessary.
forage analysis, water analysis, mineral concentrations
in feed or supplement, mineral concentrations in tissue Liver concentrations of copper, manganese,
(primarily blood, blood components, and liver tissue), selenium, and zinc provide the best indication of trace
as well as the animal’s response to treatment. mineral status (Table 2). Unfortunately, obtaining liver
samples is somewhat expensive, invasive, and time
Average dietary availability of minerals was consuming compared to blood samples. Liver iodine
considered when these requirements were determined. and iron concentration are not indicative of nutritional
Although availability of forage mineral varies with status.
the specific mineral, soil mineral concentrations, and
forage maturity and weathering, most data indicate Concentrations of minerals in whole blood or
that minerals of forage origin are between 50 and 90% blood components are frequently used because they are
available to the ruminant animal. The exception to these correlated to nutritional status, particularly for iodine,
higher absorption values is manganese, which may be iron, selenium, and zinc (Table 3). However, blood
considerably lower. concentrations of most minerals change rapidly and are
influenced by many factors other than dietary supply,
Perhaps the most useful starting point in evaluating such as calving, lactation, and other sources of stress or
mineral status is obtaining a complete mineral profile disease. Therefore, blood concentrations of any mineral
of all forages, feeds, and supplements provided to should be interpreted with caution and in conjunction
the cattle. An estimate of average daily intake of each with other assessment criteria.
component will also be necessary. Once a mineral
balance profile (daily supply minus daily requirement) Concentration of various blood enzymes and
has been constructed, marginal and severe deficiencies metabolites are also used as indicators of mineral status
can be identified. If this exercise does not reveal the in cattle. For example, glutathione peroxidase is an
Table 2. Criteria for classification of mineral status in cattle using liver mineral concentrations.
Deficient Marginal Adequate High Toxic
Cobalt 1250
Iodine 0.781
IronE-861•11
indicator of selenium status, while alkaline phosphatase,
superoxide dismutase, and metallothionein are indicators
of zinc status. Similarly, ceruloplasmin, superoxide
dismutase, and metallothionein are used as indicators of
copper status. Vitamin B12 and methylmalonic acid are
used as indicators of cobalt status.
Water intake and water mineral concentration can
also provide instructive information when assessing
mineral status of cattle. Table 4 provides recommended
maximum levels of minerals and mineral compounds in
livestock drinking water.
Supplementing Minerals
The most common method of providing
supplemental minerals to cattle is through a Figure 10. Cattle consuming mineral from a protected
protein/energy supplement or through a free-choice free-choice mineral feeder.
mineral supplement. Free-choice supplementation
requires additional equipment for delivery to cattle.
Mineral waste and spoilage from moisture can be It is important to monitor and record average daily
minimized with a number of commercially available intake of free-choice supplements so that the supplement
mineral feeders designed to minimize mineral exposure formula can be adjusted if necessary to increase or
to wind and rain (Figure 10). Animal to animal variation reduce intake. Cattle will consume salt in excess. This
in intake is greatest with free-choice mineral supplements. is why salt is used as the base ingredient in free-choice
Some cattle consume no supplement while others may supplements. Phosphorus and magnesium sources
consume as much as four or five times the intended are unpalatable and may reduce mineral supplement
daily amount. This variation is reduced considerably consumption. When providing a complete free-choice
when minerals are incorporated into protein/energy mineral supplement, all other sources of salt should be
supplements that are provided on a regular basis. removed from the pasture.
We have tracked mineral supplement disappear-
ance (which is an estimate of intake) for both spring-
Table 4. Recommended maximum levels of minerals and fall-calving cow herds at the Range Cow Research
and mineral compounds in livestock drinking water Center, North Range Unit for five years. The free-choice
(all units are mg/L except pH). mineral supplement shown in Table 5 was used. Average
mineral disappearance by cow herd and season is shown
AluminumE-861•12
Table 5. Free-choice mineral supplements for beef cows grazing low quality forage.
Free-choice mineral for Magnesium-fortified High-magnesium mineral
Ingredient beef cowsa mineral for beef cowsb for beef cowsc
Pounds per ton (as fed basis)
Dicalcium phosphate 900 700 250
Salt 570.4 435.4 500
Cottonseed meal 150 200 500
Limestone, 38% 140 140 250
Dried molasses 75 100
Selenium 600 40 40
Magnesium oxide 30 300 500
Vitamin A-30,000 IU/g 30 30
Mineral oil 20 20
Zinc sulfate 16.6 16.6
Potassium chloride 10 -
Manganous oxide 8.0 8.0
Copper sulfate 8.0 8.0
Vitamin E-50% 227,600 IU/lb 2.0 2.0
Nutrient composition (as fed basis)
Calcium, % 12 10 7
Phosphorus, % 8 6 2.5
Magnesium, % 1 8 15
Sulfur, % 0.5 0.5 -
Copper, ppm 1000 1000 -
Iron, ppmd 6250 5000 -
Manganese, ppm 2500 2500 -
Selenium, ppm 12 12 -
Zinc, ppm 3000 3000 -
a Example of a free-choice mineral for beef cows grazing native range or bermudagrass pasture. Do not feed this mineral to sheep. Daily intake should range from 2 to 4 ounces
per day.
b,c Magnesium mineral supplement should be provided when beef cattle, particularly cows, graze rapidly-growing cool-season grass or small-grains pasture. Do not feed this
mineral to sheep. Daily intake should range from 2 to 4 ounces per day.
c This mineral formula does not contain micro minerals and thus can be safely mixed at the home operation. Part or all of the cottonseed meal can be replaced with dried
molasses.
d Do not add iron oxide or other ingredients high in iron since most Oklahoma forages contain excessive iron.
The mineral formulas provided in Table 5 are pro- quality, fresh forage should contain greater than 12%
vided as examples of relatively simple free-choice min- calcium and less than 6% phosphorus. Some producers
eral mixes designed for beef cows grazing native range have fed very simple free-choice mineral supplements
during late summer and winter in Oklahoma. These for- to beef cows with excellent growth, animal health,
mulas would also be appropriate for cows consuming and reproductive performance year after year. For
other low quality forage, such as dormant Bermudagrass example, one popular homemade mineral supplement
and fescue during late summer or mid-winter. An exam- includes 50% trace-mineralized salt and 50% dicalcium
ple of a magnesium-fortified mineral supplement and a phosphate. A simple formula for supplying supplemental
high-magnesium supplement is also provided. Producers magnesium in high-risk situations is included in Table 5.
should not attempt to mix mineral supplements contain- Obviously, the major advantage of these simple formulas
ing small amounts of trace minerals at home due to po- is that they are inexpensive and they can be mixed at
tential mixing errors and the potential to cause mineral home. If a simple program like this has been used with
toxicity due to inadequate mixing. success (animal health, growth, and reproduction meets
or exceeds the expectations of the producer), there may
Lush growing forage and forage with a substantial be no need to use a more complicated and expensive
legume component contains significantly higher program. However, producers should keep in mind the
concentrations of most minerals. For example, in the potential for a production-limiting deficiency to develop.
study of Lalman et al., mineral concentration of fertilized, As discussed above, the greatest potential deficiencies
stockpiled Bermudagrass forage contained relatively in Oklahoma include vitamin A, phosphorus, copper,
high concentrations of phosphorous, potassium, sulfur, and zinc. Over a long period of time, these deficiencies
iron, and manganese during the month of November, may be revealed through reduced animal health and
when the forage regrowth was lush (high quality). performance.
Therefore, mineral supplements should contain lower
concentrations of these minerals during times when There are situations where salt is the most effective
cattle have access to high quality forage. Mineral and economical supplementation program. This is
supplementation for cattle grazing wheat pasture and particularly true when cattle consume high quality,
other cool-season annuals is discussed in Chapter 18. As lush forage, legume based forage, and/or substantial
a general rule, free-choice mineral supplements for high concentrate supplementation. For example, when stockerYou can also read
